v²/2g = h; (2)
or v = [root](2gh) = 8.025V [root]h. (2a)
[Illustration: FIG. 41.]
That is, neglecting the viscosity of the fluid, the velocity of
filaments at the contracted section of the jet is simply the velocity
due to the difference of level of the free surface in the reservoir
and the orifice. If the orifice is small in dimensions compared with
h, the filaments will all have nearly the same velocity, and if h is
measured to the centre of the orifice, the equation above gives the
mean velocity of the jet.
_Case of a Submerged Orifice._--Let the orifice discharge below the
level of the tail water. Then using the notation shown in fig. 41, we
have at M, v1 = 0, p1 = Gh; + p_a at m, p = Gh3 + p_a. Inserting these
values in (3), § 29,